IGF

IGF-1 is a peptideroughly the same structure and size as insulin, or about70 amino acids long. It belongs to the peptide family of substancesidentified as growth factors. It is a highly anabolic hormone releasedin the liver as well as in peripheral tissues such as skeletal muscle.In the body,IGF-1is released in response to the presence ofHumanGrowth Hormone(HGH).After intense resistance training, the body experiences a surge in GHand IGF, and this is one way that new muscle is built. AlthoughGHis considered to be highly anabolic, in actuality, IGF-1 is suspectedto be responsible for the primary anabolic activities of GH.

IGF-1 builds new muscle tissue by promoting nitrogen retention and proteinsynthesis. This causes the growth of muscles through both hyperplasia(which is an increase in number of muscle cells) and mitogenesis (whichis the actual growth of new muscle fibers).Thus IGF-1 not only makes musclefibers bigger, it makes more of them as well!

IGF-1’s effects are not limited to building new muscle, however. It hasa potent effect on lipid (fat) metabolism, and helps the body burn fatat a significantly elevated rate. In addition, IGF-1 is both aneuroprotector and neuropromotor, which improves mental functions suchas reflexes, memory, and learning ability. IGF is also important forproduction of connective tissue andinsuring proper bone density.

Although IGF-1 is very potent at building muscle and burning fat, theLr3 IGF-1 version is roughly 2-3x as powerful.

Lr3IGF-1 (Long R3Insulin-like Growth Factor-I or Long R3IGF-I) is an83 amino acid analog of humanIGF-I actually comprising the complete human IGF-1sequence but with the substitution of an Arg for the Glu at position 3,as well as a 13 amino acid extension peptide at the N-terminus. Thismakes Long R3IGF-I significantly more potent (2-3x) than IGF-I instudies, because it has a lower affinity to be rendered inactive by IGFbinding proteins, and consequently more potential activity in the body.